I agree with adding something to the occupations. In the 1920s Investigator's Handbook for CoC they gave bonuses to every occupation, be it an attribute bonus, a skill bonus, or immunity to certain types of Sanity loss. I think this would be a good way to emulate the different advancement schemes in Warhammer. You could also give free equipment for any occupation, like the infamous small but vicious dog.
As for Sanity/Madness, the basic system is in the BGB and is easy to import.
I don't have my copy of Magic World in my hands yet, but from what I understand characters without a POW of 16 or higher can't even cast spells. If you need magic to be more rare, then you could up that to a 17 or 18, though from my read through of Warhammer magic isn't exceedingly rare, especially if you can career jump to the apprentice for a mere 100XP (if I remember my Warhammer correctly).